To edit options, open Options (or Preferences) from application menu. For changes to take effect restart application after changing options.
Font size defines default font size in all the window editors.
Localisation selects language. List of supported languages is in drop down list.
Autosave can be disabled and interval can be adjusted.
Text processing options enables spell checking and search for synonyms.
Hotkeys can be easily overrided, just click to the needed field and press combination you want to use for this action.
Color scheme selects application coloring. Here are some examples of color schemes.